5 week old and rice cereal?

So my 5 week old who is over 11 pounds is always hungry. He was born 10 pounds 8 ounces. He’s up every hour and a half and eats about 6 ounces. It’s tiring as I expected and probably normal. My friend says she started her baby with a little bit of rice cereal in her babies bottles and they slept longer and had no other issues. Obviously I’m not going to do it without asking a doctor but has anyone else done this at such a young age?